1. Field of the Invention
The present invention relates to an information processing device having a speaker for reproducing sound information and also to a speaker unit applicable to the device.
2. Description of the Related Art
FIG. 1 is a perspective view showing a conventional information processing device by way of example. This device includes a first housing 4 having a keyboard unit 2 and a second housing 8 having a display unit 6. The second housing 8 can be opened and closed with respect to the first housing 4 through a hinge mechanism not shown. A speaker 10 is built in the second housing 8. A sound wave generated from the speaker 10 is radiated out of the housing 8 through a plurality of holes 12 formed through the housing 8.
FIG. 2 is a sectional view of the speaker 10 and its associated parts of the device shown in FIG. 1. The speaker 10 includes a frame 13 fixed to an inner surface of the housing 8, a magnetic circuit 14 fixed to the frame 13, a voice coil 16 provided so as to interlink a magnetic field generated by the magnetic circuit 14, and a vibration board 18 vibrated in accordance with movement of the voice coil 16.
When an electrical signal for reproducing sound information is passed through the voice coil 16, the voice coil 16 is moved back and forth in a lateral direction as viewed in FIG. 2 in the magnetic field given by the magnetic circuit 14. The vibration of the voice coil 16 is converted into a sound wave (compression wave in the atmospheric air) by the vibration board 18. The sound wave thus generated is radiated out of the housing 8 through the holes 12 of the housing 8.
In the conventional device shown in FIGS. 1 and 2, the holes 12 must be formed through the housing 8 to reproduce sound information, so that this device is not suitable for use in an adverse environment as in a dusty environment. Further, the speaker 10 and other electronic components built in the housing 8 are susceptable to moisture or the like in the use environment of the device.
It may be proposed to build the speaker 10 in the housing 8 without forming the holes 12 through the housing 8. In this case, however, sound cannot be reproduced or otherwise sound quality is degraded.
It is therefore an object of the present invention to provide an information processing device which can reproduce sound information with high sound quality without the need for formation of the holes for sound transmission through the housing.
It is another object of the present invention to provide a speaker unit applicable to the device.
In accordance with an aspect of the present invention, there is provided an information processing device having a first configuration. The first configuration comprises a housing, a pole piece, a voice coil, a magnet, and a frame. The housing has an elastically vibratory vibration region. The pole piece has a first end and a second end. The first end is fixed to the vibration region of the housing. The voice coil is fixed to the second end of the pole piece. The magnet forms a magnetic field interlinking the voice coil. The frame fixes the magnet to the housing at a region other than the vibration region, for example.
In accordance with another aspect of the present invention, there is provided an information processing device having a second configuration. The second configuration comprises a housing, a magnet, a voice coil, and a frame. The housing has an elastically vibratory vibration region. The magnet is fixed directly or indirectly to the vibration region of the housing. The voice coil is provided so as to interlink a magnetic field formed by the magnet. The frame fixes the voice coil to the housing at a region other than the vibration region, for example.
According to the first or second configuration, the vibration region of the housing can be directly vibrated without the use of the vibration board of the speaker in the conventional device. Accordingly, it is possible to provide an information processing device which can reproduce sound information with high sound quality without the need of formation of the holes for sound transmission through the housing. In the first configuration, vibration of the voice coil due to a current flowing through the voice coil is transmitted through the pole piece to the vibration region of the housing. In the second configuration, vibration of the magnet due to a current flowing through the voice coil is transmitted to the vibration region of the housing.
Preferably, the vibration region of the housing has a thickness smaller than that of a region of the housing other than the vibration region. With this configuration, it is possible to ensure compatibility between improvement in mechanical strength of the whole or most of the housing and improvement in frequency response characteristics in sound information reproduction. Further, since the vibration region is thin, the energy for vibration of the vibration region can be suppressed to thereby reduce a drive current to be supplied to the voice coil.
Preferably, the housing has an airtight structure. With this configuration, the device can be used even in an adverse environment as in a dusty environment in addition to the advantage that the holes for sound transmission need not be formed through the housing.
Preferably, the housing comprises a first housing having a keyboard unit and a second housing having a display unit, the second housing being openable and closable with respect to the first housing, and the vibration region is defined in the vicinity of the display unit of the second housing. In the case that the outer surface of the vibration region of the housing is plane or concave, directivity possibly occurs in sound information reproduction in the vibration region. In this respect, by defining the vibration region in the vicinity of the display unit of the second housing, sound information can be well transmitted to a user viewing the display unit, and the transmission of sound information to others is suppressed. Thus, it is possible to provide an information processing device suitable for personal use.
Preferably, the housing is formed of resin. In the case of forming the housing by injection molding of resin, for example, it is easy to make the vibration region of the housing thinner than the other region of the housing.
In accordance with a further aspect of the present invention, there is provided a speaker unit having a first configuration. The first configuration of the speaker unit comprises a pole piece, a voice coil, a magnet, a frame, and a damper. The pole piece has a first end and a second end. The first end is adapted to be fixed to a vibration region of a housing. The voice coil is fixed to the second end of the pole piece. The magnet forms a magnetic field interlinking the voice coil. The frame fixes the magnet to the housing at a region other than the vibration region, for example. The damper displaceably supports the pole piece to the frame.
In accordance with a still further aspect of the present invention, there is provided a speaker unit having a second configuration. The second configuration of the speaker unit comprises a magnet, a voice coil, a frame, and a damper. The magnet is adapted to be fixed to a vibration region of a housing. The voice coil is provided so as to interlink a magnetic field formed by the magnet. The frame fixes the voice coil to the housing at a region other than the vibration region, for example. The damper displaceably supports the magnet to the frame.
According to the first or second configuration of the speaker unit, it is possible to easily provide the first or second configuration of the information processing device according to the present invention, respectively.
The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.